Method of making coke briquettes



June 5, 19.51 F. c. KERN 2, 6

METHOD OF MAKING COKE BRIQUETTES Filed June 16, 1947 RAW COAL RAW COAL cusHE PULVERIZER BIN BIN L .SOLVENT RESINIC AG'TATOR CASPHALTIC)SUBSTANCE WET-PAN GRINDER DISINTEGRATOR BRIQUETTING I DRY, I owTEMPERATURE coKE GASIFIER DISTILLATION B ENZOL c A s PRIMARY TA R OILS Go K E FRAc T IONAL DISTILLATION I I I I I LIGHT MIDDLE HEAVY REsIwE.ARTIFICIAL OILS oII s OILS ASPHALT 0R PITcI-I INVENTOR Patented June 5,1951 UNITED STATES PATENT OFFICE 2,556,154 METHOD OF MAKING coKEBRIQUETTES Fernando C. Kern, St. Louis, Mo.

Application June 16, 1947, Serial No. 754,965

2 Claims. 1

This invention relates to improvements in the carbonization of coal soas to produce coke and valuable by-products, and more particularly tosuch a method whereby there will be a maximum yield of tar toilstogether with coke, of the very highest quality. 7

The invention is related generally to that described in Patent No.1,899,089, issued February 28, 1933, to Ludwig Kern and myself. In saidpatent, the coal is described as bein ground to 150 mesh or finer, andto such powdered coal there is added enough of an alkali in aqueoussolution to react with the freed ash-forming constituents of the coal,to form a plastic binder therewith, which through suitable homogenizing,plasticizes the entire mass into a firm moldable body from which thebriquettes are formed. These briquettes are thereafter dried, and thensubjected to distillation or carbonization to recover the volatiles andto form coke. However, tests have shown that although the process iseificient with some coals, yet with others the results were not entirelysatisfactory.

The instant invention, although related to the teachings of said patent,difiers therefrom in important aspects, and the results seem uniformlybetter. Principally, it differs in that the alkali is replaced by ahydrocarbon compound that is liquid or semi-liquid at normal roomtempera tures, and which is chemically a close ally to all types of coaland analogous carboniferous' materials.

One of the important objects of my invention is to provide a processthat is extremely flexible in its application, and wherein the solidcarboniierous materials may be treated separately or in combinations,depending upon their physical and chemical make-ups, as for example, bycombining and treating bituminous, semi-bituminous and sub-bituminouscoals alone, or in combination with anthracites or other substantiallyresinic-free coals.

Other important objects of my invention are to provide a method oftreating materials of the kind described, so that various types of solidcarbonaceous products may be produced, as for example, semi-cokebriquettes readily ignitible at about the same temperatures asbituminous coal but which will burn smokeless and without requiringdraft, so that it is an ideal fuel for domestic use; an artificialanthracite having all of the desirable properties thereof, but which isignitible at from 100 to 200 C. lower temperature than said naturalanthracite; ina brick form suitable for blast furnaces, foundries, in-

dustrial furnaces and boilers; or to coal gasification, hydrogenation,and for other products requiring high fixed-carbon content.

A further object of my invention is to pro- 5 vide a process of treatingsolid carbonaceous fuel, so that a favorable exchange is brought abouttherein in the quantity, speed, and chemical constitution of theby-product hydrocarbons derived therefrom, and at relatively lowtemperatures.

An added object of my invention is to produce a conversion of highlyvolatile bituminous coal, rich in resinic content, into relatively largeyields of primary tar oils of low specific gravity, averaging between.95 and 1.06, and of relatively low boiling points, said oils beingcomposed mainly of saturated and unsaturated paraflines, olefine's,naphthenes, high-molecular hydrocarbons, and being especially rich inmiddle oils that contain the highly-prized homologues of the phenolicseries.

Another object of my invention is to produce sufficient porosity in thecoal being treated, so that it absorbs the plasticizing medium properlywhile at normal room temperature.

Anaddition'al object of my invention is to practice the invention byintermixing the coal with a liquid or semi-liquid hydrocarbon compoundflowable at room temperature and having a boiling point of approximately125 to 300, C. and which in contradistinction to water, has a highaffinity for coal, so as to agglomerate and agglutinize therewith andact as a solvent for the resinic constituents thereof, and in itselfhaving lubricating, coking and distillable properties to therebyincrease the fixed and reactive carbon content of the coke.

A still further object of my invention is to produce a method of thekind described, that will not only recover the volatiles inherent in thecoal, but in addition, will recover those that may have been addedthereto in the carrying out or this process, and whereby the process maybe"- come cyclic and self-contained.

Other added objects of my invention are provide a method setforth,wherein the added constituents are introduced at room temperat'ure,carbonization commenced without drying of the briquettes and carried onat low tempera tures, and wherein the coal is changed into a moldableand shape-retaining briquettable mass prior to carbonization.

To this end, my invention consists in the novel process herein shown anddescribed, and the ingredients used, as will be more clearlypointed outin the claims hereunto appended;

In the drawings, there is illustrated diagrammatically, a flow sheet ofthe sequence of steps in the practice of the invention.

In carrying out my invention, I may use practically any coal, although Iprefer to use a bitu-,

minous coal for many reasons, as will be more clearly understood fromthe disclosures hereof, and it may be mentioned that low-grade coals areadmirably suited to suchuse. For example, I have successfully used alow-grade Illinois coal running about percent ash, 3 percent sulphur, 12percent moisture, 38 percent volatiles and 3'7 percent fixed carbon, andby treatment by this process have converted the same into a high-gradesemi-coke briquette containing about 78 to 83 percent fixed carbon,easily ignitible and burnable without draft and entirely'free of visiblesmoke; thus enabling the use of such briquettes even in those localitieshaving the most stringent anti-smoke regulations.

Such solid carbonaceous fuel, preferably acoal high in resinic content,as for example the bituminous coals, is crushed or otherwise comminutedto pass through a 30 to 40 standard mesh screen. Fuel, either from thesame source, or from another source, may be prepared to a more finelycomminuted state, so that it becomes pulverized and will pass throughabout a 200 mesh screen. If desired, this pulverized coal may be sheet,and from whence they may be withdrawn as needed.

As coal, no matter what its fineness, is not moldable at roomtemperature except possibly under unusually great pressure, without somes-ortof a binder, it will be seen that I have minimized this difficulty,and my process enables the briquetting at relatively low pressure androom temperature, and wherein the briquettes will retain their shapethrough carbonization and through the subsequent-handling, includingrelatively rough handling.

I have found that coarse and pulverized coals in about the proportionsstated will agglutinize under certain conditions without an extraneousbinder, at relatively low pressure and at normal room temperature, byintroducing said coals into a wet pan grinder and agitator wherein heavysteel mullers move, with a slight amount of water, and after saidmullers have acted for a short time, say about 15' or minutes thereon,to grind, compress, knead and lubricate the mixture, it becomes changedin its chemical and phy-' sical form to an elastic, rubber-like lumpymass or slab, and the resinic content of the coals have been forced fromtheir original places and states of deposit into the very pores of thecoal and especially into the capillary openings formed between thecoarse and the pulverized coal particles,

However, I have found that for best results, it is desirable that anadditive be incorporated into the coals that are to be intermixed, andhave termed this additive an important ingredient of the hydrocarboncompound, the compound comprising such additive or additives together 4with the pulverzied coal, as will be more clearly hereinafter set forth.

The carrier or diluent for this hydrocarbon compound is liquid orsemi-liquid at normal room temperature, with a boilin point rangingbroadly between 125 and 300 0., and has the power of being a solventfor'the volatiles or resinic content of the coal. Such carrier maybederived from various sources and may include those from coal tar orpetroleum, including the first fractions or light oils from distillationor carbonization,

and may be generally termed hydrocarbon naphtha.

In the commencement of my operations such liquid may have to be obtainedfrom an extraneous source, but after the process has gotten under way,sufiicient amounts may be taken off and returned into the operations tothereby make it a cyclic process. This solvent acts as a vehicle for theresinic constituents of the coal.

If the liquid or semi-liquid hydrocarbon having the foregoingcharacteristics does not have enough resinic content for the carryingout of this process to best advantage, it may be necessary to add'suchresinic or asphaltic substance, and it is to be noted although thisresinic substance may be obtained from an extraneous source, yet it canbe taken from the residue end of the fractional distillation in myprocess and returned into the cycle, so that both such resinicsubstances and the hydrocarbon naphtha are taken from the process itselfand introduced at the stage where mixture with the coal is had, andwhereby the process is a cyclic one. This resinic 'or asphalticsubstance, sometimes called pitch,

is preferably in powdered form of about the same fineness as thepulverized coal.

This resinic substance and the liquid or semiliquid hydrocarbondescribed, are preferably intermixed with the pulverized coal, usingjust enough of the liquid to make intoa paste of the desiredconsistency, and which takes about 20 gallons of the liquid to about 350kilos of the 'pulverized coal. r r

' Now, in order to better enable the components of this hydrocarboncompound (the liquid hydrocarbon, resinic asphaltic substance andpulverizedcoal) to react fully with one another, it is introduced intoan agitator or the like, wherein it is intimately homogenized, with orwithout heating.

Next, the pulverized coal so treated is introduced in the form of saidhydrocarbon compound, into a wet pan grinder and agitator, Wheretogether with added coarser coal, in about the proportions stated, heavysteel mullers roll, oompress, grind, knead and otherwise most intimatelyintermix the same to'form the contents into an agglutinized,agglomerated lumpy slab of elastic rubber-like mass. The entire physicaland chemical structure of the mass has thereby become so chan.g ed andsp0nge-like,'that a piece will withstand the impact of a 25 to 30 footdrop onto a brick floor without breaking or chipping. Such material maybe readily shaped into formretaining briquettes at room temperature,with compartively low pressure, say With up to 5000 pounds per squareinch, depending on the moisture content.

It will be found that the absorbed compound envelopes all of the coalparticles with a distinct.

individual coating, acting as the vehicle for lubricating,'agglomerating and otherwise binding into such physical characteristicthat the particles permit of compression into the briquettes at lowpressure. If, in the mixing of the mass, there is not enough moisturefor proper molding and briquetting, as will be apparent from visualinspection, additional fluidity may be obtained by added Water. Althoughit is well-known that bituminous coal is by nature water-repellent andchemically inert, yet it is made to change its characteristics andbecome spongy and rubher-like after the aforesaid treatment, and capableof absorbing about close to one-half of its weight in litiuidhydrocarbon, and that a 55 gram briquette for example holds enoughmoisture to be reduced to approximately 30 grams after carbonization.

When the mixing has terminated and the charge has assumed. the slab-likeand rubberylike elastic structure mentioned, and which generally takesonly about 15 minutes or so, depending upon the varying conditions thatmay be encountered, the mass is then preferably disintegrated orfragmentized by suitable means, and then, either in such fragments orafter shaping into briquettes under relatively light pressure, it isready for carbonization and distillation without drying.

This elastic mass, shaped or not, as preferred, is carbonized anddistilled at relatively low temperatures, as will be more clearlyhereinafter set forth, and the crude tar oils obtained will have a lowspecific gravity and low boiling points and may be separated orfractionated in the well-known manner.

The liquid hydrocarbon naphthas added to the pulverent mass beforecarbonization act in the beat of dry carbonization upon the resinic partof the coal, dissolving, extracting and separating the same from thefixed carbon and ash constituents of the coal. This action takes placeat low temperatures, and this results in increasing the mechanicalstrength of the resultant coke, and besides, accelerates extraction.Carbonizing takes place in from 2 to 6 hours with my method, as comparedwith from 20 to 25 hours in the old gas-making and coke-oven methods,with equal amounts or" coal.

It will be noted from the chart, that this very important hydrocarbonliquid can, after it has performed its function, be reclaimed in therecovery of the primary tar oils, and can be returned cyclically, in theprocess, as can the pitch.

The first fractions, the light oils, are taken off between to 170 0.,having a specific gravity of about .860, and include naphthas, benzol,toluol, xylol, some phenols.

The second fractionating stage, between 170 and 270 0., recovers themiddle oils, having a specific gravity of about .970, and includeshomologues of the phenolic series, phenol derivatives, cresols, creosoteoils, carbolics, etc.

The third fractionating stage, between 270 and 360 0., recovers theheavy oils, with a specific gravity of about between .990 and 1.000, andbesides some of the middle oil may include some anthracene oil.

Above 360 0., remains the residue of pitch or artificial asphalticsubstance, and which may provide the resinic substance for the carryingout of this process.

The foregoing temperatures and gravities may vary within fairly widelimits, depending upon the basic materials employed, and thereforechanges in carbonization and fractionating will suggest themselves tothe operators. It is to be again stressed that the light oil, thehydrocarbon naphtha, as well as the pitch, may be returned cyclically,to the process.

If desired, said residue tar may be further treated for recovery ofvaluable constituents, or to refine the same.

It may be more economical or expedient when starting operation, tosubstitute for said coaltar naphtha, another naphtha having sufficientlylike properties to enable its use herein, as for example some otherhydrocarbon naphtha, say petroleum naphtha, having about the sameboiling-points and being similarly fiowable at normal room temperature.Such a distillate may be of the aromatic, aliphatic or napthenic seriesor equivalent solvents, and to which may be added a small amount ofphenolic compounds, cresols, xylenols, and the higher phenols, thusenhancing the solvency of the naphthas.

It will be found that the mass remaining after the agglutinizing, isspongy and porous, with a consequent irregularity of its cellularstructure,

and this is ofgreat importance as it permits of. rapid passing of thevapors and gases from the briquettes into the condensors at relatively10W temperatures. Such unobstructed volatilization of the tar vaporsprotects the briquettes from severe secondary decomposition and loss ofvery valuable primary tar oils. The usual swelling of the briquettes atthe plastic stage of carbonization, generally caused by the accumulatedand entrapped gases and vapors between 350 and 450 C., is eliminated,and localized overheating of hydrocarbon vapor into pyrogenedecomposition is eliminated.

Other advantages obtained by the increasing of porosity of the coal arethat there results accelerated and economical conversion of the coal,besides the unobstructed passage of vapors, without overheating.

If desired, the coke remaining after carbonization as above describedmay be treated further, and preferably while still hot, by transferrencewhile under exclusion of air, to a suitable coking retort, and gasesextracted for further treatment.

It is well known that in crushing coal so as to pass through a standardmesh 20 to 30 per inch, about one-third to one-fourth of the coal willbe reduced to dust of a fineness sufiicient to pass through about a 200mesh screen. Since this proportion of crushed coal to dust is about thesame proportion used in my invention, the process is very economical.Further, it is not necessary in making a paste by adding a hydrocarbonoil and resinic substances to the dust to first separate the dust fromthe coarse particles of coal; as the dust will be taken into suspensionby the hydrocarbon oils without such separation.

Having thus described my invention, it is obvious that variousimmaterial modifications may be made in the same without departing fromthe spirit of my invention; hence I do not wish to beunderstood aslimiting myself to the exact process herein set forth and described,except as limited by the state of the art to which this inventionappertains, and by the claims hereunto appended.

What I claim as new and desire to secure by Letters Patent is:

1. A method of converting highly bituminous coal into coke briquettescomprising crushing the coal to pass a 30 to 40 mesh screen, to providerelatively coarse particles, preparing additional coal to pass anapproximately 200 mesh screen, to provide pulverized particles, addingliquid 7. naphtha to the pulverized coal in the proportion of about 20gallons of naphtha to 350 kilograms of pulverized coal, addingpulverized pitch of about the same fineness to the pulverized coal andnaphtha, mixing and agitating the pulverized coal, naphtha and pitch inthe absence of water to form a paste, adding to the paste two to threetimes as much by weight of the coarse coal particles, with respect tothe amount of pulverized coal in the paste, intermixing the coarseparticles and paste by a combined rolling, crushing, grinding andkneading action at room temperature, adding enough water to maintainfluidity during the intermixing, continuing the rolling, crushing,grinding and kneading for about 15 minutes, whereby the mixture becomesrubbery and slab-like, pressure-molding such rubbery and slab-likematerial into briquettes, and carbonizing said briquettes.

2. A method of converting highly bituminous coal into coke briquettescomprising crushing the coal to pass a 30 to 40 mesh screen, to providerelatively coarse particles, preparing additional coal to pass anapproximately 200 mesh screen, to provide pulverized particles, addingliquid naphtha to the pulverized coal in the proportion of about 20gallons of naphtha to 350 kilograms of pulverized coal, addingpulverized pitch of about the same fineness to the pulverized coal andnaphtha, mixing and agitating the pulverized coal, naphtha and pitch'inthe absence of water to form a paste, adding to the paste two to threetimes as much by weight of the coarse coal particles, with respect tothe amount of pulverized coal in the paste, intermixing the coarseparticles and paste by a combined rolling, crushing, grinding andkneading REFERENCES CITED The following references are of record in thefile of this patent:

UNITED STATES PATENTS Number Name Date 332,613 Kelly Dec. 15, 1885755,278 Cruikshank Mar. 22,1904 857,287 a Jordan June 18, 1907 1,430,386Komarek 1 Sept. 26, 1922 1,512,427 Trent Oct. 21, 1924 1,561,322 GoskarNov. 10, 1925 1,618,248 Walton Feb. 22, 1927 1,647,075 Bowen Oct. 25,1927 1,667,906 Strafford May 1, 1928 1,825,756 Reynard Oct. 6, 19311,842,132 4 Trent Jan. 19, 1932 1,899,808 Kern Feb. 28, 1933 1,899,809Kern Feb. 28, 1933 1,929,860 Trent Oct. 10, 1933 FOREIGN PATENTS NumberCountry Date 274,046 Great Britain Aug. 24, 1928 421,556 Great BritainDec. 24, 1934 448,622 Great Britain June 8, 1936 521,152 Great BritainMay 14, 1940

1. A METHOD OF CONVERTING HIGHLY BITUMINOUS COAL INTO COKE BRIQUETTESCOMPRISING CRUSHING THE COAL TO PASS A 30 TO 40 MESH SCREEN, TO PROVIDERELATIVELY COARSE PARTICLES, PREPARING ADDITIONAL COAL TO PASS ANAPPROXMATELY 200 MESH SCREEN, TO PROVIDE PULVERIZED PARTICLES, ADDINGLIQUID NAPHTHA TO THE PULVERIZED COAL IN THE PROPORTION OF ABOUT 20GALLONS OF NAPHTHA TO 350 KILOGRAMS OF PULVERIZED COAL, ADDINGPULVERIZED PITCH OF ABOUT THE SAME FINENESS TO THE PULVERIZED COAL ANDNAPHTHA, MIXING AND AGITATING THE PULVERIZED COAL, NAPHTHA AND PITCH INTHE ABSENCE OF WATER TO FORM A PASTE, ADDING TO THE PASTE TWO TO THREETIMES AS MUCH BY WEIGHT OF THE COARSE COAL PARTICLES, WITH RESPECT TOTHE AMOUNT OF PULVERIZED COAL IN THE PASTE, INTERMIXING THE COARSEPARTICLES AND PASTE BY A COMBINED ROLLING, CRUSHING, GRINDING ANDKNEADING ACTION AT ROOM TEMPERATURE, ADDING ENOUGH WATER TO MAINTAINFLUIDITY DURING THE INTERMIXING, CONTINUING THE ROLLING, CRUSHING,GRINDING AND KNEADING FOR ABOUT 15 MINUTES, WHEREBY THE MIXTURE BECOMESRUBBERY AND SLAB-LIKE, PRESSURE-MOLDING SUCH RUBBERY AND SLAB-LIKEMATERIAL INTO BRIQUETTES, AND CARBONIZING SAID BRIQUETTES.